qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [PATCH v2 5/5] vfio-ccw: add handling for async channel ins


From: Cornelia Huck
Subject: [Qemu-devel] [PATCH v2 5/5] vfio-ccw: add handling for async channel instructions
Date: Mon, 21 Jan 2019 12:03:54 +0100

Add a region to the vfio-ccw device that can be used to submit
asynchronous I/O instructions. ssch continues to be handled by the
existing I/O region; the new region handles hsch and csch.

Interrupt status continues to be reported through the same channels
as for ssch.

Signed-off-by: Cornelia Huck <address@hidden>
---
 drivers/s390/cio/Makefile           |   3 +-
 drivers/s390/cio/vfio_ccw_async.c   |  91 ++++++++++++++++++++++
 drivers/s390/cio/vfio_ccw_drv.c     |  45 +++++++----
 drivers/s390/cio/vfio_ccw_fsm.c     | 114 +++++++++++++++++++++++++++-
 drivers/s390/cio/vfio_ccw_ops.c     |  13 +++-
 drivers/s390/cio/vfio_ccw_private.h |   9 ++-
 include/uapi/linux/vfio.h           |   2 +
 include/uapi/linux/vfio_ccw.h       |  12 +++
 8 files changed, 269 insertions(+), 20 deletions(-)
 create mode 100644 drivers/s390/cio/vfio_ccw_async.c

diff --git a/drivers/s390/cio/Makefile b/drivers/s390/cio/Makefile
index f230516abb96..f6a8db04177c 100644
--- a/drivers/s390/cio/Makefile
+++ b/drivers/s390/cio/Makefile
@@ -20,5 +20,6 @@ obj-$(CONFIG_CCWGROUP) += ccwgroup.o
 qdio-objs := qdio_main.o qdio_thinint.o qdio_debug.o qdio_setup.o
 obj-$(CONFIG_QDIO) += qdio.o
 
-vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o vfio_ccw_fsm.o
+vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o vfio_ccw_fsm.o \
+       vfio_ccw_async.o
 obj-$(CONFIG_VFIO_CCW) += vfio_ccw.o
diff --git a/drivers/s390/cio/vfio_ccw_async.c 
b/drivers/s390/cio/vfio_ccw_async.c
new file mode 100644
index 000000000000..604806c2970f
--- /dev/null
+++ b/drivers/s390/cio/vfio_ccw_async.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Async I/O region for vfio_ccw
+ *
+ * Copyright Red Hat, Inc. 2019
+ *
+ * Author(s): Cornelia Huck <address@hidden>
+ */
+
+#include <linux/vfio.h>
+#include <linux/mdev.h>
+
+#include "vfio_ccw_private.h"
+
+static ssize_t vfio_ccw_async_region_read(struct vfio_ccw_private *private,
+                                         char __user *buf, size_t count,
+                                         loff_t *ppos)
+{
+       unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
+       loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
+       struct ccw_cmd_region *region;
+       int ret;
+
+       if (pos + count > sizeof(*region))
+               return -EINVAL;
+
+       mutex_lock(&private->io_mutex);
+       region = private->region[i].data;
+       if (copy_to_user(buf, (void *)region + pos, count))
+               ret = -EFAULT;
+       else
+               ret = count;
+       mutex_unlock(&private->io_mutex);
+       return ret;
+}
+
+static ssize_t vfio_ccw_async_region_write(struct vfio_ccw_private *private,
+                                          const char __user *buf, size_t count,
+                                          loff_t *ppos)
+{
+       unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
+       loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
+       struct ccw_cmd_region *region;
+       int ret;
+
+       if (pos + count > sizeof(*region))
+               return -EINVAL;
+
+       if (private->state == VFIO_CCW_STATE_NOT_OPER ||
+           private->state == VFIO_CCW_STATE_STANDBY)
+               return -EACCES;
+       if (!mutex_trylock(&private->io_mutex))
+               return -EAGAIN;
+
+       region = private->region[i].data;
+       if (copy_from_user((void *)region + pos, buf, count)) {
+               ret = -EFAULT;
+               goto out_unlock;
+       }
+
+       vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_ASYNC_REQ);
+
+       ret = region->ret_code ? region->ret_code : count;
+
+out_unlock:
+       mutex_unlock(&private->io_mutex);
+       return ret;
+}
+
+static void vfio_ccw_async_region_release(struct vfio_ccw_private *private,
+                                         struct vfio_ccw_region *region)
+{
+
+}
+
+const struct vfio_ccw_regops vfio_ccw_async_region_ops = {
+       .read = vfio_ccw_async_region_read,
+       .write = vfio_ccw_async_region_write,
+       .release = vfio_ccw_async_region_release,
+};
+
+int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private)
+{
+       return vfio_ccw_register_dev_region(private,
+                                           VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD,
+                                           &vfio_ccw_async_region_ops,
+                                           sizeof(struct ccw_cmd_region),
+                                           VFIO_REGION_INFO_FLAG_READ |
+                                           VFIO_REGION_INFO_FLAG_WRITE,
+                                           private->cmd_region);
+}
diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 2ef189fe45ed..d807911b8ed5 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -3,9 +3,11 @@
  * VFIO based Physical Subchannel device driver
  *
  * Copyright IBM Corp. 2017
+ * Copyright Red Hat, Inc. 2019
  *
  * Author(s): Dong Jia Shi <address@hidden>
  *            Xiao Feng Ren <address@hidden>
+ *            Cornelia Huck <address@hidden>
  */
 
 #include <linux/module.h>
@@ -23,6 +25,7 @@
 
 struct workqueue_struct *vfio_ccw_work_q;
 static struct kmem_cache *vfio_ccw_io_region;
+static struct kmem_cache *vfio_ccw_cmd_region;
 
 /*
  * Helpers
@@ -104,7 +107,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
 {
        struct pmcw *pmcw = &sch->schib.pmcw;
        struct vfio_ccw_private *private;
-       int ret;
+       int ret = -ENOMEM;
 
        if (pmcw->qf) {
                dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
@@ -118,10 +121,13 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
 
        private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
                                               GFP_KERNEL | GFP_DMA);
-       if (!private->io_region) {
-               kfree(private);
-               return -ENOMEM;
-       }
+       if (!private->io_region)
+               goto out_free;
+
+       private->cmd_region = kmem_cache_zalloc(vfio_ccw_cmd_region,
+                                               GFP_KERNEL | GFP_DMA);
+       if (!private->cmd_region)
+               goto out_free;
 
        private->sch = sch;
        dev_set_drvdata(&sch->dev, private);
@@ -149,7 +155,10 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
        cio_disable_subchannel(sch);
 out_free:
        dev_set_drvdata(&sch->dev, NULL);
-       kmem_cache_free(vfio_ccw_io_region, private->io_region);
+       if (private->cmd_region)
+               kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
+       if (private->io_region)
+               kmem_cache_free(vfio_ccw_io_region, private->io_region);
        kfree(private);
        return ret;
 }
@@ -238,7 +247,7 @@ static struct css_driver vfio_ccw_sch_driver = {
 
 static int __init vfio_ccw_sch_init(void)
 {
-       int ret;
+       int ret = -ENOMEM;
 
        vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
        if (!vfio_ccw_work_q)
@@ -248,20 +257,30 @@ static int __init vfio_ccw_sch_init(void)
                                        sizeof(struct ccw_io_region), 0,
                                        SLAB_ACCOUNT, 0,
                                        sizeof(struct ccw_io_region), NULL);
-       if (!vfio_ccw_io_region) {
-               destroy_workqueue(vfio_ccw_work_q);
-               return -ENOMEM;
-       }
+       if (!vfio_ccw_io_region)
+               goto out_err;
+
+       vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
+                                       sizeof(struct ccw_cmd_region), 0,
+                                       SLAB_ACCOUNT, 0,
+                                       sizeof(struct ccw_cmd_region), NULL);
+       if (!vfio_ccw_cmd_region)
+               goto out_err;
 
        isc_register(VFIO_CCW_ISC);
        ret = css_driver_register(&vfio_ccw_sch_driver);
        if (ret) {
                isc_unregister(VFIO_CCW_ISC);
-               kmem_cache_destroy(vfio_ccw_io_region);
-               destroy_workqueue(vfio_ccw_work_q);
+               goto out_err;
        }
 
        return ret;
+
+out_err:
+       kmem_cache_destroy(vfio_ccw_cmd_region);
+       kmem_cache_destroy(vfio_ccw_io_region);
+       destroy_workqueue(vfio_ccw_work_q);
+       return ret;
 }
 
 static void __exit vfio_ccw_sch_exit(void)
diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index f6ed934cc565..72912d596181 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -3,8 +3,10 @@
  * Finite state machine for vfio-ccw device handling
  *
  * Copyright IBM Corp. 2017
+ * Copyright Red Hat, Inc. 2019
  *
  * Author(s): Dong Jia Shi <address@hidden>
+ *            Cornelia Huck <address@hidden>
  */
 
 #include <linux/vfio.h>
@@ -69,6 +71,81 @@ static int fsm_io_helper(struct vfio_ccw_private *private)
        return ret;
 }
 
+static int fsm_do_halt(struct vfio_ccw_private *private)
+{
+       struct subchannel *sch;
+       unsigned long flags;
+       int ccode;
+       int ret;
+
+       sch = private->sch;
+
+       spin_lock_irqsave(sch->lock, flags);
+
+       /* Issue "Halt Subchannel" */
+       ccode = hsch(sch->schid);
+
+       switch (ccode) {
+       case 0:
+               /*
+                * Initialize device status information
+                */
+               sch->schib.scsw.cmd.actl |= SCSW_ACTL_HALT_PEND;
+               ret = 0;
+               private->state = VFIO_CCW_STATE_BUSY;
+               break;
+       case 1:         /* Status pending */
+       case 2:         /* Busy */
+               ret = -EBUSY;
+               break;
+       case 3:         /* Device not operational */
+       {
+               ret = -ENODEV;
+               break;
+       }
+       default:
+               ret = ccode;
+       }
+       spin_unlock_irqrestore(sch->lock, flags);
+       return ret;
+}
+
+static int fsm_do_clear(struct vfio_ccw_private *private)
+{
+       struct subchannel *sch;
+       unsigned long flags;
+       int ccode;
+       int ret;
+
+       sch = private->sch;
+
+       spin_lock_irqsave(sch->lock, flags);
+
+       /* Issue "Clear Subchannel" */
+       ccode = csch(sch->schid);
+
+       switch (ccode) {
+       case 0:
+               /*
+                * Initialize device status information
+                */
+               sch->schib.scsw.cmd.actl = SCSW_ACTL_CLEAR_PEND;
+               /* TODO: check what else we might need to clear */
+               ret = 0;
+               private->state = VFIO_CCW_STATE_BUSY;
+               break;
+       case 3:         /* Device not operational */
+       {
+               ret = -ENODEV;
+               break;
+       }
+       default:
+               ret = ccode;
+       }
+       spin_unlock_irqrestore(sch->lock, flags);
+       return ret;
+}
+
 static void fsm_notoper(struct vfio_ccw_private *private,
                        enum vfio_ccw_event event)
 {
@@ -103,6 +180,14 @@ static void fsm_io_busy(struct vfio_ccw_private *private,
        private->io_region->ret_code = -EAGAIN;
 }
 
+static void fsm_async_error(struct vfio_ccw_private *private,
+                           enum vfio_ccw_event event)
+{
+       pr_err("vfio-ccw: FSM: halt/clear request from state:%d\n",
+              private->state);
+       private->cmd_region->ret_code = -EIO;
+}
+
 static void fsm_disabled_irq(struct vfio_ccw_private *private,
                             enum vfio_ccw_event event)
 {
@@ -165,11 +250,11 @@ static void fsm_io_request(struct vfio_ccw_private 
*private,
                }
                return;
        } else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
-               /* XXX: Handle halt. */
+               /* halt is handled via the async cmd region */
                io_region->ret_code = -EOPNOTSUPP;
                goto err_out;
        } else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
-               /* XXX: Handle clear. */
+               /* clear is handled via the async cmd region */
                io_region->ret_code = -EOPNOTSUPP;
                goto err_out;
        }
@@ -179,6 +264,27 @@ static void fsm_io_request(struct vfio_ccw_private 
*private,
                               io_region->ret_code, errstr);
 }
 
+/*
+ * Deal with an async request from userspace.
+ */
+static void fsm_async_request(struct vfio_ccw_private *private,
+                             enum vfio_ccw_event event)
+{
+       struct ccw_cmd_region *cmd_region = private->cmd_region;
+
+       switch (cmd_region->command) {
+       case VFIO_CCW_ASYNC_CMD_HSCH:
+               cmd_region->ret_code = fsm_do_halt(private);
+               break;
+       case VFIO_CCW_ASYNC_CMD_CSCH:
+               cmd_region->ret_code = fsm_do_clear(private);
+               break;
+       default:
+               /* should not happen? */
+               cmd_region->ret_code = -EINVAL;
+       }
+}
+
 /*
  * Got an interrupt for a normal io (state busy).
  */
@@ -202,21 +308,25 @@ fsm_func_t 
*vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
        [VFIO_CCW_STATE_NOT_OPER] = {
                [VFIO_CCW_EVENT_NOT_OPER]       = fsm_nop,
                [VFIO_CCW_EVENT_IO_REQ]         = fsm_io_error,
+               [VFIO_CCW_EVENT_ASYNC_REQ]      = fsm_async_error,
                [VFIO_CCW_EVENT_INTERRUPT]      = fsm_disabled_irq,
        },
        [VFIO_CCW_STATE_STANDBY] = {
                [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
                [VFIO_CCW_EVENT_IO_REQ]         = fsm_io_error,
+               [VFIO_CCW_EVENT_ASYNC_REQ]      = fsm_async_error,
                [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
        },
        [VFIO_CCW_STATE_IDLE] = {
                [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
                [VFIO_CCW_EVENT_IO_REQ]         = fsm_io_request,
+               [VFIO_CCW_EVENT_ASYNC_REQ]      = fsm_async_request,
                [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
        },
        [VFIO_CCW_STATE_BUSY] = {
                [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
                [VFIO_CCW_EVENT_IO_REQ]         = fsm_io_busy,
+               [VFIO_CCW_EVENT_ASYNC_REQ]      = fsm_async_request,
                [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
        },
 };
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 5a89d09f9271..755806cb8d53 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -148,11 +148,20 @@ static int vfio_ccw_mdev_open(struct mdev_device *mdev)
        struct vfio_ccw_private *private =
                dev_get_drvdata(mdev_parent_dev(mdev));
        unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
+       int ret;
 
        private->nb.notifier_call = vfio_ccw_mdev_notifier;
 
-       return vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
-                                     &events, &private->nb);
+       ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+                                    &events, &private->nb);
+       if (ret)
+               return ret;
+
+       ret = vfio_ccw_register_async_dev_regions(private);
+       if (ret)
+               vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+                                        &private->nb);
+       return ret;
 }
 
 static void vfio_ccw_mdev_release(struct mdev_device *mdev)
diff --git a/drivers/s390/cio/vfio_ccw_private.h 
b/drivers/s390/cio/vfio_ccw_private.h
index 20e75f4f3695..ed8b94ea2f08 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -31,9 +31,9 @@ struct vfio_ccw_private;
 struct vfio_ccw_region;
 
 struct vfio_ccw_regops {
-       size_t  (*read)(struct vfio_ccw_private *private, char __user *buf,
+       ssize_t (*read)(struct vfio_ccw_private *private, char __user *buf,
                        size_t count, loff_t *ppos);
-       size_t  (*write)(struct vfio_ccw_private *private,
+       ssize_t (*write)(struct vfio_ccw_private *private,
                         const char __user *buf, size_t count, loff_t *ppos);
        void    (*release)(struct vfio_ccw_private *private,
                           struct vfio_ccw_region *region);
@@ -53,6 +53,8 @@ int vfio_ccw_register_dev_region(struct vfio_ccw_private 
*private,
                                 const struct vfio_ccw_regops *ops,
                                 size_t size, u32 flags, void *data);
 
+int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private);
+
 /**
  * struct vfio_ccw_private
  * @sch: pointer to the subchannel
@@ -64,6 +66,7 @@ int vfio_ccw_register_dev_region(struct vfio_ccw_private 
*private,
  * @io_region: MMIO region to input/output I/O arguments/results
  * @io_mutex: protect against concurrent update of I/O structures
  * @region: additional regions for other subchannel operations
+ * @cmd_region: MMIO region for asynchronous I/O commands other than START
  * @num_regions: number of additional regions
  * @cp: channel program for the current I/O operation
  * @irb: irb info received from interrupt
@@ -81,6 +84,7 @@ struct vfio_ccw_private {
        struct ccw_io_region    *io_region;
        struct mutex            io_mutex;
        struct vfio_ccw_region *region;
+       struct ccw_cmd_region   *cmd_region;
        int num_regions;
 
        struct channel_program  cp;
@@ -115,6 +119,7 @@ enum vfio_ccw_event {
        VFIO_CCW_EVENT_NOT_OPER,
        VFIO_CCW_EVENT_IO_REQ,
        VFIO_CCW_EVENT_INTERRUPT,
+       VFIO_CCW_EVENT_ASYNC_REQ,
        /* last element! */
        NR_VFIO_CCW_EVENTS
 };
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 56e2413d3e00..8f10748dac79 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -354,6 +354,8 @@ struct vfio_region_gfx_edid {
 };
 
 #define VFIO_REGION_TYPE_CCW                   (2)
+/* ccw sub-types */
+#define VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD      (1)
 
 /*
  * 10de vendor sub-type
diff --git a/include/uapi/linux/vfio_ccw.h b/include/uapi/linux/vfio_ccw.h
index 2ec5f367ff78..cbecbf0cd54f 100644
--- a/include/uapi/linux/vfio_ccw.h
+++ b/include/uapi/linux/vfio_ccw.h
@@ -12,6 +12,7 @@
 
 #include <linux/types.h>
 
+/* used for START SUBCHANNEL, always present */
 struct ccw_io_region {
 #define ORB_AREA_SIZE 12
        __u8    orb_area[ORB_AREA_SIZE];
@@ -22,4 +23,15 @@ struct ccw_io_region {
        __u32   ret_code;
 } __packed;
 
+/*
+ * used for processing commands that trigger asynchronous actions
+ * Note: this is controlled by a capability
+ */
+#define VFIO_CCW_ASYNC_CMD_HSCH (1 << 0)
+#define VFIO_CCW_ASYNC_CMD_CSCH (1 << 1)
+struct ccw_cmd_region {
+       __u32 command;
+       __u32 ret_code;
+} __packed;
+
 #endif
-- 
2.17.2




reply via email to

[Prev in Thread] Current Thread [Next in Thread]